<Button>:
    font_size: 20
    size_hint: 0.2, 0.2

<RelativeLayoutWidget>:

    BoxLayout:

    RelativeLayout:
        Button:
            text: "Bt0"
            background_color: 0.1, 0.5, 0.6, 1
            pos_hint: {"right": 1, "top": 1}

        Button:
            text: "Bt1"
            background_color: 1, 0, 0, 1
            pos_hint: {"x": 0, "top": 1}

        Button:
            text: "Relative"
            background_color: 0.4, 0.5, 0.6, 1
            pos_hint: {"center_x": 0.5, "center_y": 0.5}

        Button:
            text: "Bt2"
            background_color: 0, 0, 1, 1
            pos_hint: {"x": 0, "y": 0}

        Button:
            text: "Bt3"
            background_color: 0.8, 0.9, 0.2, 1
            pos_hint: {"right": 1, "y": 0}
